Isothermal damper



(No Model.)

J. H. HALDEMAN.

ISOTHERMAL DAMPER.

No. 391,844l Patented Oct. 30, 1888.

AMM, /mw @541% llhvirnn STATES Arnv'r @arrent JOHN H. HALDEMAN, OF VESTFIELD, MASSAOHUSETTS.

lSOTHERIVIAL DlVlPER.

PBCFCATIN forming part of Letters Patent No. 391,844, dated o'cober EO, 1888.

Application filed Marcl3l,1887.

To all whom, it' may concern:

e it known that I, JOHN H. HALDEMAN, a citizen of the United States of America, residing in Vestfield, in the county of Hampden and State of Massachusetts, have invented new and useful Improvcments in Isothcrmal Danpers, 'of which the following is a specification, reference being had to the accompanying drawings and letters of reference marked thereon.

The object of my invention is to provide a renovable device for stoves which shall be compact and complete in itself and of simple and cheap construction,and Which shall be free from the objections which obtain against a dampcr wherein a curvcd expansion-rod is used; and to that end my invention consists in a plate or stove-lid having attached to it a movable plate and'a straight expansion-rod fixed at one end to the plate or lid and extended across the face of the plate or lid,with its free cnd connected by means of one or more levers to the movable plate, whereby the sane is caused to move by the expansion or contraction of the expansion-rod; and, further, it consists in the general construction and arrangement herein set out,wl1ereby the objects of myinvention are attained.

In the accompanying drawings, in which like letters of reference indicate like parts, Figure l is a top view of a stove-cover having my device applied thereto. Fig. 2 is a View of the same inverted. Fig. 3 is a View of a modification. Fig. 4. is a view of my device as applied to a stove-pipe damper'. Figs. 5 and 6 are views of detached parts of the device, and Fig. 7 is an under side View of the part of the stove-lid a between lines :tw of Fig. 2.

eferring to the drawings in detail, a indicatesastove-lid having openings b. cindicates a plate centrally pivoted to the under side of the lid and having openingsj. d indicates a strip of metal which expands when heated and contracts when cold. c indicates a bellcrank lever pivoted to the stove-lid. f indicates a plate as usually used for a stove-pipe damper, and g, h, and t' indicate levers for the purpose of increasing the motion. 4

The construction will be seen to be simple and inexpensive, and although I have illustratcd the application of my invention to a .gages the plate c near il's pivotal point.

Serial No. 233,105. model the openings in the lid; or radial arms inay I be used instead of the plate, they being attached to the central pivoted portion of the device. The plate is pivoted to the center of the under side of the lid, and a brass rod,

cZ, slotted at one end for the purpose of adf justment, is secured at one end to the lid by a nut or set-screw, k, and is pivotally counected at its opposite end with the short arm of the bellcrank lever c. The lever c is pivoted to the lid at or near the elbow of the lever, and the end of the longer arm eu- The platc is held in place by a nut or setscrew, l. If, now, the device be placed upon a heated stove,the rod d will expand in the direction of its length, and one end being fastened firmly to the lid its opposite end will cause the short arm of the bell-crank lever c, to which it is pivotally attached, to move outwardly, thus causing the end of the long arm of the lever e to move to one side of its normal position, thus causing the plate c, with which the long arm of the lever c engages,to turn on its pivot until the openings in the plate register with the openings in the cover, thus allowing air to enter the fire-box and thus reducing the draft and allowing the firc to die out until the temperature is so reduced that the rod d contracts, and, being immovably fastened at k, the lever and. plate are moved by the coutraction in the opposite direction and the openings closed, thus increasing'the draft and automatically maintaining the fire at an even temperature.

The pivotal point of connection of the eX- pansion-rod d with the bell-crank lever c is indicated by the letter yr in Fig. ``7,and of the bell-crank lever e with the lid a by the letter s. The pivotal pointofconnectiou of the plate c with the lid a is indieated by the letter Z.

The same construction is applied to the IOO stove-pipe damper, except that the platec and rod and levers are set so that when the damper is turned to a position to close the opening in the pipe the openings in the pivot-al plate c will register with the openings in the damperplatef, and the application of heat and eonsequent expansion of the rod d will operate to cause the pivotal plate to turn and cover the openings, thus obstructing the draft and operating to check and maintain'the fire at the desired point. The rod d is slotted at the end at which it is fastened, to enable the same to be adjusted from time to time as circumstances may require.

In some instances the notion imparted by the expansion of the comparatively short rod (Z will not be sufficient to move the damper or covering-plate a sufficient distance. This may occur where the space in which the rod d may be located is very limited, or where but slight variation of temperature is had, and consequently but slight expansion and contraction results. ln such cases I multiply the motion by attaching the long arm of the bell-crank lever to the short arm of one or more levers and connecting these auxiliary levers by their long arm to the pivotal plate c, thus obtaining the requisite movement under very slight variations of temperature. I illustrate one method of accomplishing this in Fig. 3 of the drawings, thelong arm of the bell-crank lever e being attached to the short arm of a lever, h, through the medium of a connecting-rod, g, The lever his pivoted to the lid, and an opening, m, madein the plate to permit of the pivotal connection without interfering with the motion of the plate. The long arm of the lever h is connected with the pivoted plate by a rod, i, so that the expansion and contraction of the rod d operate to cause the plate to move and open or close the openings in the same manner as before described, though a less variation in temperature is required to obtain the same motion of the plate.

I am aware-that a stove-door has heretofore been constructed provided with a swinging door hinged to open away from the stove-door, and provided with an expansion-rod and levers to cause the swinging door to open and to operate a pointer indicating the temperature in the oven, and that a damper has heretofore been made provided with an expansionrod located above and outside of the damperplate, which rod operates to open the damper, and the weight of the damper-plate operates to close it, and I make no claim to the construction of such devices. My device differs in detail of construction, method of operation of the parts, and arrangenent of the parts.

Of course the shape and location of the parts and shape of the openings may be greatly varied as circumstances may direct.

Having therefore described my invention, what I claim, and desire to secure by Letters Patent, is*- 1. An isothermal damper consisting of a circular plate, a, having openings and having centrally pivoted thereto a part or plate, c, which turns on its pivot in a plane parallel with the face of plate a, and a` straight expan- Sion-rod fixed at one end to plate a, near its outer edge, and extended across the plate near its center, and having its free end connected at a point near the opposite edge of plate a with a lever which engages with and operates in the combination to turn the part c on its pivot, all in combination, substantially as shown.

A2. The combination of a stove-lid having openings through it, a plate, c, provided with like openings and centrally pivoted to the under side of the lid to turn on its pivot in a plane parallel with the face of the lid, an expansion-rod, d, fixed at one end to the under side of the lid near its outer edge, and a bellcrank lever, e, pivoted at or near its elbow to the under side of the lid, the short arm of which lever engages the free end of the expansion-rod and the long arm of which engages the part c, substantially as shown.

3. A plate, a, having openings, a movable plate, c, pivoted thereto and arranged to cover or expose the openings in plate a, a straight expansion-rod fixed at one end to plate a and extended across plates a and c, and a lever, e, pivoted to plate aand having its short arm connected wit-li the free end of the expansion-rod and its long arm engaging plate c, whereby the expansion or contraction of the expansionrod will cause the turning of plate c on its pivot, substantially as stated.

4. As an improved article of manufacture, an isothermal damper for regulating drafts in stoves, Sto., consisting of the combination of a plate, a, provided with openings, a movable plate, c, pivoted to plate a, a straight expansion-rod, d, fixed at one end to plate a, and multiplyinglevers, as e, g, Iz,, and i, connecting the free end of the expansion-rod with the novable plate, all the parts being united to and operating on the plate a, substantially as shown.

JOHN II. HALDEMAN.

lVitnesscs:

ALLEN Wnns'rnn, CHAs. R. CULVER.

IOO 

